This pilot study will assess the effects of gender and exogenous hormones on hepatic cytochrome P450 3A4 activity in men and women. The primary objective is to compare the mean intrasubject coefficient of variation (C.V.) of the ratio of urinary 6-B-hydroxycortisol to cortisol (6-B-)H-cortisol:cortisol), determined over a four week period, among the three study groups: women not receiving exogenous hormones, women receiving Triphasil, and men. Secondary objectives include use of a second metabolic probe, dextromethorphan, and estrogen and progesterone concentrations to further assess these gender differences.